This application claims the priority of German Patent Document, filed Jan. 14, 1998, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a process and system for braking a vehicle.
Processes and systems have been known for some time which sense changes of the bodily reaction of a human being, particularly of the driver of a motor vehicle, which point to emergency/stress situations. DE 38 35 726 A1 discloses, for example, a steering wheel contact sensor ring switch for controlling audio-visual warning systems, engine stop and emergency braking devices on motor vehicles. A warning signal is emitted and a braking operation is initiated when the driver's hands grip not only around the steering wheel.
DE 296 21 896 U1 discloses a switch-off device for a vehicle cruise control. The gas supply is interrupted and the cruise control is switched off when the driver's hands no longer have a grip around the vehicle steering wheel.
DE 197 02 748 A1 discloses a process for monitoring the condition of a human being, particularly of the driver of a motor vehicle. The head position and/or the cerebral flows and/or the muscular system and/or the breathing of the human being or the pressure at which the steering wheel is gripped are monitored or sensed continuously and/or at intervals. In the event of a threatening change of a bodily reaction, which points to an emergency/stress situation, a warning signal is emitted. Particularly the alertness of the driver of a motor vehicle is to be determined in this manner.
DE 44 22 664 A1 an EP 0 706 466 B1 describe a system and a process in which an automatic braking operation of a vehicle is triggered in the event of a reflex-type change of the position of the foot on the accelerator pedal from a first position to a second position. Such a reflex-type change of the position of the driver's right foot points to an emergency/stress situation.
Furthermore, so-called "brake assistant systems" are known. The operating speed of the brake pedal is sensed and, on the basis thereof a conclusion is drawn on an emergency/stress situation. If such a situation exists, an automatic emergency braking is initiated.
As the result of these processes and systems for initiating an automatic emergency braking, the braking distance of the vehicle is considerably reduced. However, these processes and systems have the disadvantage that, when an emergency situation arises, it always takes some time for the driver to react. This time comprises a reflex and reaction time period. That is, the time period is the time which passes until the driver understands the situation and reacts in that the driver's right foot is removed from the accelerator pedal and moved in the brake pedal direction in order to operate the brake pedal.